Methamphetamine (MA), like other drugs of abuse, poses a significant personal and societal threat in the United States. Furthermore, MA use appears to be increasing while use of many other drugs of abuse is declining. To gain a greater insight into the initiation, maintenance, and consequences of MA use and abuse, we must examine the factors that covary with drug dependence. One variable that has been found to covary with drug-dependence status is future discounting. Future discounting refers to the subjective decrease in the value of an outcome that is at some temporal distance in the future. Rate of future discounting is higher in various drug-dependent populations (relative to controls), including abstinent MA users. However, recent exploration of the discounting construct indicates that subjective value of outcomes decrease as a function of other dimensions of psychological distance: namely past temporal distance, probabilistic distance, and social distance. To date, no studies have comprehensively examined the various form of discounting by active MA users. Furthermore, no studies have comprehensively examined the relationships between the various forms of discounting. Given the public health implications of MA use and abuse, it is important to expand current knowledge about future, past, probability, and social discounting by active MA users relative to non-users. This research may provide new insights into the variables that affect decision-making in general, and MA and other forms of drug dependence in particular, leading to new modules of treatment that supplement effective treatments regimens in use today. The long-term objective of this line of research is to further knowledge about the variables that influence behavior such as MA use, and to facilitate the development of comprehensive treatment programs for drug dependence. The first specific aim of this proposal is to compare and contrast future, past, probability, and social discountin by active MA users and non-users. The second specific aim of this proposal is to evaluate possible relationships between the various forms of discounting (future, past, probability, social). If discounting by active MA users are found to be greater than that by non-using controls, and the various forms of discounting are found to be related, the current knowledge regarding the variables that affect MA (and other drug use) use could supplement methods current used to prevent and treat MA use and abuse. PUBLIC HEALTH RELEVANCE: Methamphetamine use, abuse, and dependence is a growing concern in the United States, contributing to a variety of personal and societal consequences including medical illness, psychiatric disorder, violence, and environmental toxicity. Effective prevention and treatment of current MA use, abuse, and dependence is necessary in order to address these significant consequences. The current proposal attempts to examine behavioral phenomena relevant to active MA use and other forms of drug dependence.